solve can't handle certain multi-equation settings

[kcrisman]

See this ask.sagemath question. Basically, at least in certain situations involving abs(), you

var('x y a b')
f=[1+y-a*abs_symbolic(x)==x, b*x==y]; f
solve(f, [x, y])

gives boom, or more precisely

TypeError: cannot coerce arguments: no canonical coercion from <type 'list'> to Symbolic Ring

since it somehow is trying to make this into one object. But

assume(x>0)
solve(f, [x, y])

gives not boom. So somehow our code for recognizing when we have a system of equations isn't working right in the first case. Note that

var('x y a b')
f=[1+y-a*x==x, b*x==y]
solve(f,[x,y]

apparently works fine.

Component: symbolics

Issue created by migration from https://trac.sagemath.org/ticket/22149

[mkoeppe]

comment:1

still the same in 9.4.beta4